A self-contained breathing apparatus (SCBA) used by a firefighter generally includes a pressurized air cylinder for supplying breathable air, a pressure regulator, an inhalation connection (mouthpiece, mouth mask or face mask) and other devices mounted to a frame that is carried by the firefighter. The configuration of the air cylinder is typically a result of the consideration of several design factors. These include items such as size, weight, amount of air supply required, portability, compatibility with other standardized equipment and the like. Current air cylinders for firefighters are pressurized to approximately 2216 pounds per square inch (psi) or 4500 psi.
In use, it is desirable to provide a SCBA with sufficient air capacity that the user is not limited in his/her work by having to exit the site to obtain replacement air cylinders. Increased air capacity must, however, be balanced with the need to have a manageable SCBA both in terms of weight and space. In this regard, several configurations of air cylinders have been utilized to provide a desired air capacity. In one configuration, two standard size air cylinders are used to provide additional air capacity. In another configuration, multiple reduced profile air cylinders are used to provide improved maneuverability while maintaining desired capacity. Since these configurations require the use of more than one cylinder, however, they can undesirably result in increased weight. They also can be cumbersome to handle and can require the use of specialized equipment and the retraining of fire department personnel in order to assure proper operation.
In still other configurations, air cylinders are fabricated from specialized materials such as carbon fiber composite to provide a cylinder pressure of 9,500 psi or higher. Such configurations, while providing a desirable increased air capacity, also result in increased costs of production. Such configurations also may result in increased weight.
Thus, it would be desirable to provide an improved air cylinder having a reduced overall space envelope while maintaining existing air capacity. The resulting cylinder should be easy to use, inexpensive to manufacture and should be compliant with current cylinder charging infrastructure.